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CIHM/ICMH 

Microfiche 

Series. 


CIHM/ICIVIH 
Collection  de 
microfiches. 


Canadian  Institute  for  HIatorlcal  MIcroreproductlona  /  Instltut  Canadian  de  mlcroreproductlona  historlquee 


Tachnical  and  Bibliographic  Notaa/Notas  tachniquaa  at  bibliograpliiquaa 


Tha 
toti 


Tha  Instiiuta  has  attamptad  to  obtain  tha  bast 
original  sopy  availabia  for  filming.  Faaturaa  of  this 
copy  which  may  ba  bibliographicaliy  uniqua, 
which  may  altar  any  of  tha  imagas  in  tha 
raproduction,  or  which  may  significantly  changa 
tha  usual  mathod  of  filming,  ara  chackad  balow. 


□    Colourad  covars/ 
Couvartura  da  coulaur 


I — I   Covars  damagad/ 


D 


D 


D 
D 


D 


D 


Couvartura  andommagAa 


Covars  rastorad  and/or  laminatad/ 
Couvartura  rastaurAa  at/ou  pallicuMa 


I — I   Covar  titia  missing/ 


La  titra  da  couvartura  manqua 


I     I   Colourad  maps/ 


Cartas  giographiquas  9n  coulaur 


Colourad  ink  (i.a.  othar  than  blua  or  black)/ 
Encra  da  coulaur  (i.a.  autra  qua  blaua  ou  noira) 


I     I   Colourad  platas  and/or  illustrations/ 


Planchas  at/ou  illustrations  9n  coulaur 


Bound  with  othar  matarial/ 
RaliA  avac  d'autras  documants 


Tight  binding  may  causa  shadows  or  distortion 
along  intarior  margin/ 

La  re  liura  sarria  paut  causar  da  I'ombra  ou  da  la 
distortion  la  long  da  la  marga  int^riaura 

Blank  laavas  addad  during  rastoration  may 
appaar  within  tha  taxt.  Whanavar  possibia,  thaaa 
hava  baan  omittad  from  filming/ 
II  sa  paut  qua  cartainas  pagas  blanchas  aJoutAas 
lors  d'una  rastauration  apparaissant  dans  la  taxta, 
mala,  lorsqua  cala  Atait  possibla.  cas  pagas  n'ont 
pas  4t4  filmtes. 

Additional  commants:/ 
Commantairas  supplAmantairaa; 


L'Institut  a  microfilm*  la  maillaur  axamplaire 
qu'il  lui  a  *ti  possibla  da  sa  procurer.  Las  details 
da  cat  axamplaira  qui  sont  paut-Atra  uniquas  du 
point  da  vua  bibliographiqua.  qui  pauvant  modifier 
una  imaga  raproduita,  ou  qui  pauvant  axiger  una 
modification  dans  la  mithoda  normala  da  filmage 
sont  indiqute  ci-dassous. 


I     I   Colourad  pagas/ 


Pagaa  da  coulaur 

Pagas  damaged/ 
Pagas  andommagias 


□   Pagas  restored  and/or  laminated/ 
Pagas  restaurAas  at/ou  pellicuiies 

rTf  Pagas  discoloured,  stained  or  foxed/ 


01 


Tha 
post 
ofti 
film 


Ori( 
bag 
tha 
aior 
oth( 
firsi 
sion 
or  II 


Pages  dAcoiories,  tachet6es  ou  piquies 


Pagas  detached/ 
Pages  ditachies 


I     I   Showthrough/ 


D 


Transparence 

Quality  of  priti 

Quality  inigaia  da  I'imprassion 

Includes  supplementary  matarii 
Comprend  du  material  supplimantaire 

Only  edition  available/ 
Saule  Edition  disponible 


rn   Quality  of  print  varies/ 

I     I   Includes  supplementary  material/ 

|~~|   Only  edition  available/ 


Tha 
shal 
TIN 
whi 

Mai 
diff 
ant! 
bag 
righ 
raqi 
met 


Pages  wholly  or  partially  obscured  by  errata 
slips,  tissues,  etc.,  have  been  refilmed  to 
ensure  the  best  possible  image/ 
Lea  pages  totalament  ou  partiellement 
obscurcies  par  un  feuillet  d'errata,  una  peiure, 
etc..  ont  M  film^es  A  nouveau  da  fa? on  A 
obtanir  la  mailleure  imaga  possible. 


This  item  is  filmed  at  tha  reduction  ratio  chackad  below/ 

Ca  document  est  film*  au  taux  da  reduction  Indlqu*  ci-dassous. 


10X 


14X 


18X 


22X 


26X 


30X 


7 


12X 


16X 


aox 


a4x 


28X 


32X 


ails 

du 

difiar 

una 

laga 


The  copy  filmed  here  hae  been  reproduced  thank* 
to  the  generosity  of: 

Matropditan  Toronto  LilMrary 
Canadian  Hiitory  Dapartmant 

The  imaoet  appearing  here  are  the  beet  quality 
poeaibie  eonaidering  the  condition  end  legibility 
of  the  original  copy  and  in  keeping  with  the 
filming  contract  specif Icetlons. 


L'exemplaire  film*  f ut  reproduit  grice  k  la 
gAnirositA  de: 

Matropolltan  Toronto  Library 
Canadian  History  Dapartmant 

Les  images  suivantes  ont  4t4  reproduites  avec  le 
plus  grend  soin,  compte  tenu  de  le  condition  et 
de  la  nettet*  de  rexemplaire  fiimA,  et  en 
conformiti  avec  les  conditions  du  contrat  de 
fiimage. 


Original  copies  in  printed  paper  covers  ere  filmed 
beginning  with  the  front  cover  and  ending  on 
the  last  page  with  a  printed  or  iiluatrated  Impres- 
sion, or  the  back  cover  when  appropriate.  All 
other  original  copies  are  filmed  beginning  on  the 
first  page  with  a  printed  or  illustrated  impres- 
sion, and  ending  on  the  last  page  with  a  printed 
or  illustrated  impre&aion. 


Les  exempiairei  originaux  dont  la  couverture  en 
pepier  est  imprimte  sont  fllmfo  en  commenpant 
par  le  premier  plat  et  en  termlnent  soit  par  la 
dernlAre  page  qui  comporte  une  empreinte 
d'impression  ou  d'illustration,  soit  par  le  second 
plat,  salon  le  cas.  Tous  les  autres  exempiaires 
originaux  sont  filmfo  on  commenpent  par  la 
premlAre  page.qui  comporte  une  empreinte 
d'impression  ou  d'illustration  et  en  termlnent  par 
la  dernlAre  page  qui  comporte  une  telle 
empreinte. 


The  last  recorded  frame  on  each  microfiche 
shall  contain  the  symbol  ^^-  (meaning  "CON- 
TINUED"), or  the  symbol  ▼  (meaning  "END"), 
whichever  applies. 


Un  das  symboles  suivants  apparaTtra  sur  la 
derniAre  image  de  cheque  microfiche,  selon  le 
cas:  le  symbols  — ►  signifie  "A  SUIVRE",  le 
symbols  V  signifie  "FIN". 


Maps,  plates,  cherts,  etc..  may  be  filmed  et 
different  reduction  ratios.  Those  too  large  to  be 
entirely  included  in  one  exposure  are  filmed 
beginning  in  the  upper  left  hend  corner,  left  to 
right  and  top  to  bottom,  as  many  frames  as 
required.  The  following  diagrama  illustrate  the 
method: 


Les  csrtes.  pisnches.  tableaux,  etc..  peuvent  Atre 
fiimAs  A  dee  taux  de  rMuction  diffArents. 
Lorsque  le  document  est  trop  grend  pour  Atre 
reproduit  en  un  seul  clichA.  il  est  filmA  A  partir 
de  I'angle  supArieur  geuche.  de  geuche  h  droite. 
et  de  heut  en  bes,  en  prenant  le  nombre 
d'images  nAcessaire.  Les  diagrammes  suivanta 
illustrent  la  mAthode. 


rata 


elure, 


3 


32X 


1 

2 

3 

1 

2 

3 

4 

5 

6 

BULLETIN  OF  THE  GEOLOGICAL  SOCIETY  OF  AMERICA 

Vol.  1,  pp.  395-410 


H-T.^"^ 


POST-TERTIARY  DEPOSITS  OP  MANITOBA  AND  THE  AD- 
JOINING TERRITORIES  OF  NORTHWESTERN  CANADA 


BT 

J.  B.  TYRRELL 

OF  TBK  QROLOOIOAL  BURVKY  Or  CANADA 


WASHINGTON 

PUBLISHED  BY  THIS  SOCIETY 

Apbil,  1890 


'S 


5S6> 


'5i 


i: 


"ffiiT^^^if^^^ny  ^^^'^  -'a  7 


-^^•y 


BULLETIN  OF  THE  GEOLOGICAL  SOCIETY  OF  AMERICA 
Vol.  1,  pp.  396-410  April  17,  189o 


r 


•i, 


POST-TERTIARY  DEPOSITS  OF   MANITOBA  AND  THE  AD- 
JOINING TERRITORIES  OF  NORTHWESTERN  CANADA. 

BY  J.  B.  TYRRELL,  OP  THE  GEOLOGICAL  SURVEY  OP  CANADA. 

{Rend  before  the  Society  Deeemher  27,  1889.) 

CONTENTS. 

Page. 

The  Region  and  its  Genornl  Geological  Features 895 

The  Glacial  Deposits.. _ „ 896 

Till - 39« 

Terminal  Moniines 398 

Absence  of  Terminal  Moraines  near  the  Rocky  Mountains 401 

Western  Pebbles 401 

Direction  of  Ice  Flow 401 

Deposits  of  Isolated  Glaciers 402 

Drumlins 402 

The  Aqueous  Deposits 402 

Interglacial  Deposits. 402 

Karnes 408 

Lacustral  Beds 408 

Ancient  Beaches 404 

Discussion . 407 


I 


■■i 


The  Region  and  its  General  Geological  Features. 

Southwest  of  the  margin  of  what  has  long  been  known  as  the  Archean 
continental  nucleus  lies  a  great  drift-covered  area,  including  in  it  most  of  the 
plains  and  prairies  of  northwestern  Canada.  It  extends  on  the  international 
boundary  line  from  the  western  side  of  the  Lake  of  the  Woods  to  near  the 
eastern  base  of  the  Rocky  Mountains,  through  between  sixteen  and  seven* 
teen  degrees  of  longitude,  or  a  distance  of  more  than  750  miles.  Towards 
the  northwest  it  stretches  along  the  face  of  the  Archean  area  to  beyond  the 
arctic  circle  in  the  valley  of  the  Mackenzie  river. 

Lying  on  an  irregular  floor  of  old  gneisses  and  schists,  rocks  of  Silurian 
and  Devonian  age  are  known  to  occur  over  the  whole  eastern  and  north- 
eastern portion  of  this  district,  while  further  westward  these  disappear  under 
others  of  upper  Mesozoic  age;  and  thence  westward  to  the  foot  of  the  Rocky 

Lll— Bolt..  Gkoi,.  Soc.  Am.,  Voi,.  1, 1889.  (895) 


■'X.- 


396       J.   B.   TYRKELL — POST-TERTIARY  DEPOSITS  OP  MANITOBA. 

Mountains,  Cretaceous  or  Tertiary  beds  everywhere  underlie  the  post-Tertiary 
or  recent  deposits.  The  character  of  most  of  these  beds,  which  consist  of 
sandstones,  marls,  and  clay-shales,  is  perfectly  well  known,  but  I  wish  to 
draw  your  attention  for  a  moment  to  the  occurrence  of  conglomerates  of 
Miocene  and  Pliocene  age,  the  existence  of  which  has  been  pointed  out  of 
late  years,  since  they  furnish  sources  of  supply  for  a  large  amount  of  drift 
which  was  formerly  supposed  to  have  been  derived  directly  from  the  Rooky 
Mountains  at  the  same  time  that  the  other  associated  portions  of  the  drift 
were  derived  from  the  Archean  and  Paleozoic  rocks  to  the  east. 

The  Miocene  is  at  present  known  as  a  fresh-water  formation  of  sands, 
silts,  and  gravel,  or  conglomerate,  lying  on  the  eroded  surface  of  the  Creta- 
ceous and  Laramie  rocks  on  the  more  elevated  portions  of  the  Hand  and 
Cypress  hills,  and  on  the  higher  plateaus  stretching  east  from  these  as  far  as 
long.  107*'  15'.  The  pebbles  in  this  conglomerate  are  all  well  rounded  and 
waterwom,  and  consist  of  a  white  quartzite  similar  to  that  in  the  Rocky 
Mountains  described  by  Mr.  McConnell  as  belonging  to  his  "  Bow  River 
group,"  or  lower  portion  of  the  Cambrian  system.  This  material  has  been 
carried  eastward  by  rapid  streams  during  Miocene  times,  and  deposited  either 
in  lakes  or  on  the  flood-plains  of  rivers.  The  gravel  has  in  many  places 
been  indurated  by  the  infiltration  of  a  calcareous  cement  into  a  hard  con- 
glomerate, much  harder  than  the  underlying  shales  and  sandstones,  and  has 
preserved  the  hills  that  it  now  covers  from  degradation  by  atmospheric  and 
fluviatile  agencies  to  the  same  extent  as  the  surrounding  country,  and  at  the 
same  time  has  furnished  a  scale  by  which  to  measure  the  thickness  of  the 
rocks  washed  away  since  Miocene  times. 

The  Pliocene,  here  called  by  Mr.  McConnell  the  "  South  Saskatchewan 
group,"  is  also  composed  of  rounded  quartzite  gravel ;  but  it  now  occupies  the 
bottoms  of  valleys  or  other  depressions,  and  has  been  derived  in  part  from 
the  pre-existing  Miocene  deposits,  and  also  in  part  directly  from  the  quartzite 
areas  of  the  mountains. 

The  district  under  consideration,  extending  from  the  boundary  between 
the  United  States  and  Canada  northward  to  the  North-Saskatchewan  river, 
is  largely  overlain  by  a  series  of  heterogeneous  deposits  which  are  commonly 
embraced  under  the  term  "  drift."  This  consists  of  bowlder  clay  or  till, 
morainic  detritus  including  erratics,  drumlins,  kames,  alluvial  sands,  clays, 
and  silts,  beach-ridges,  terraces,  etc. 


The  GiiAciAii  Deposits. 

TiU. — ^The  bowlder  clay  or  till  rests  irregularly  on  all  the  pre-glacial 
formations  down  to  the  fundamental  gneisses  and  schists,  ».nd  in  the  Archean 
area  itself  fills. many  protected  depressions  and  recesses.  It  does  not,  how- 
ever, reach  the  base  of  the  Rooky  Mountains,  bnt  extends  westward  to  within 


TILL  OF  THE  8A8KATCHEWAN   PLAINS. 


397 


forty  miles  of  them,  as  far  as  Calgary,  on  the  Canadian  Pacific  railway,  and 
from  there  southward  to  the  international  boundary  it  keeps  at  about  the 
same  distance  from  the  mountains.  North  of  Calgary  the  western  edge  of 
the  great  sheet  of  till  crosses  the  Red  Deer  and  North-Saskatchewan  rivers 
at  approximate  elevations  of  3,000  feet  above  the  sea,  the  latter  in  long. 
115°  W.  Further  north  it  is  stated  by  Dr.  Dawson  to  cross  the  Peace  river 
in  lat.  56°  N.,  long.  119°  W.  To  the  south  its  boundary  everywhere  lies 
on  the  United  States  side  of  the  Forty-ninth  parallel  of  latitude.  North 
of  or  near  this  geodetic  line  it  covers  all  the  country  of  the  plains  without 
regard  to  elevation,  with  four  exceptions,  viz.,  the  upper  portions  of  the 
Sweet  Grass  hills  above  4,660  feet,  the  Cypress  hills  above  4,400  feet,  the 
Hand  hills  above  3,400  feet,  and  Rocky  Spring  plateau  above  4,100  feet. 
The  general  character  of  this  great  sheet  of  drift  is  remarkably  uniform 
throughout,  being  essentially  composed  of  a  gray,  more  or  less  sandy  clay, 
massive  in  character,  and  holding  numerous  pebbles  and  bowlders.  It  is 
largely  composed  of  the  debris  of  the  Cretaceous  and  Tertiary  rocks  that 
surround  or  immediately  underlie  it,  consisting  probably  of  the  parts  of 
these  strata  that  were  rotten  from  long  exposure  to  the  weather  during  the 
ages  that  intervened  between  the  close  of  the  Laramie  period  and  the  com- 
mencement of  that  of  glaciation.  By  this  latter  agency  the  rotten  rock  was 
kneaded  up,  with  the  bowlders  and  pebbles  transported  from  a  di>  .«.n.-!e,  into 
a  homogeneous  mass.  That  the  till  is  local  is  clearly  seen  where  the  under- 
lying rock  has  any  very  marked  characteristic  by  which  it  can  be  recog- 
nized—as, for  instance,  the  rocks  of  the  Edmonton  series  of  the  Laramie, 
which  are  associated  with  numerous  beds  of  lignite.  Overlying  these  rocks, 
and  especially  for  some  distance  south  of  a  lignite  outcrop,  the  drift  is  filled 
with  pieces  of  lignite  sometimes  as  large  as  a  hen's  egg,  and  the  whole  mass 
becomes  dark  in  color  from  its  presence  in  minute  fragments.  Another  in- 
stance is  recorded  by  Dr.  Dawson  where  the  drift  has  a  distinctly  reddish 
tint,  derived  from  some  neighboring  reddish  clays  of  the  Laramie  formation. 
The  bowlders  are,  however,  largely  of  eastern  origin,  being  composed  of 
granitoid  gneiss,  mica-schist,  quartzite,  diabase-trap,  gneiss-conglomerate, 
and  stratified  Paleozoic  limestone,  those  of  limestone,  as  well  as  an  occa- 
sional one  of  the  other  rocks,  being  usually  irregular  in  shape,  with  smooth, 
polished  surfaces  and  sharply  marked  glacial  strise.  The  pebbles  included 
in  the  till  throughout  the  western  portion  of  the  district,  where  they  consist 
largely  of  white  quartzite,  the  same  as  that  composing  the  Miocene  gravels 
on  the  Cypress  and  Hand  hills,  are  doubtless  partly  of  local  origin,  having 
been  derived  from  the  gravel  on  these  hills,  or  from  other  areas  that  have 
been  entirely  denuded  away.  Some  are  also  probably  derived  from  the 
parent  beds  of  Cambrian  quartzites  in  the  Rocky  Mountains.  A  few  of 
gneiss  are  almost  everywhere  met  with,  and  while  the  western  quartzites 


I 


■"1i 


\ 


308       J.    B.   TYRRKLL — I'OST-TERTIARY   DEPOSITS  OF  MANITOBA. 

gradually  disappear  ou  proceeding  eastward  those  of  gneiss  become  more 
numerous,  and  pebbles  of  Paleozoic  limestone  also  become  very  common. 

In  thickness  the  till  varies  greatly  in  different  places,  ranging  down  from 
500  feet  or  more  to  a  very  thin  covering ;  but,  generally  speaking,  throwing 
out  of  account  deposits  clearly  referable  to  terminal  moraines,  it  becomes 
slightly  thinner  from  east  to  west,  the  outcrops  seen  along  the  3,00()-foot 
contour  line  above  mentioned  being  as  a  rule  not  more  than  a  few  feet  in 
thickness. 

Throughout  the  greater  portion  of  the  area  under  consideration  the  till 
falls  naturally  into  two  major  subdivisions,  a  lower  very  compact  bluish- 
gray  unstratified  deposit,  and  an  upper  softer  and  sometimes  thickly  lamel* 
lated  clay  usually  of  a  light  brownish  color.  These  two  subdivisions  have 
been  chiefly  recognized  in  the  extreme  western  portion  of  the  area,  from  the 
international  boundary  north  to  the  North-Saskatchewan  river,  where  they 
are  often  separated  by  stratified  waterlaid  deposits,  in  which,  on  the  Belly 
river.  Dr.  Dawson  records  the  occurrence  of  a  bed  of  lignite  eight  inches  in 
thickness.  The  till  in  this  latter  locality  is  also  of  extraordinary  thickness 
as  compared  with  the  average  found  farther  north  between  the  Bow  and 
North-Saskatchewan  rivers.  Farther  east  these  two  subdivisions  have  not 
been  so  generally  recognized,  probably  on  account  of  the  great  thickness 
of  the  whole  deposit  and  the  comparative  paucity  of  good  sections. 

Terminal  Moraines. — Intimately  associated  with  the  till  are  a  number  of 
irregular  ridges  of  rounded  hills  severed  by  deep  depressions,  in  the  bottoms 
of  which  are  often  lakelets  of  clear,  sweet  water  without  visible  outlets. 
The  rim  of  the  basin  of  one  of  these  lakes  is  frequently  fifty  or  sixty  feet 
above  the  surface  of  the  water,  and  surrounding  knolls  in  many  cases  rise  to 
a  height  of  from  a  hundred  to  a  hundred  and  fifty  feet  higher.  Sections  of 
these  hills  show  them  to  be  masses  of  transported  material,  consisting  of  un- 
stratified sand,  clay,  and  bowlders,  and  their  sides  and  summits  are  almost 
always  thickly  strewn  with  large  northern  or  eastern  erratics. 

As  to  the  mode  of  formation  of  these  hilly  tracts,  there  is  now  little  room 
for  doubt  that  they  were  the  terminal  moraines  of  one  or  more  extensive 
glaciers  that  moved  outwards  from  the  central  Archean  nucleus,  planing  off 
the  higher  points  of  the  surface  and  shoving  before  them  the  accumulated 
mass  of  mixed  material.  Much  of  this  fell  back  under  the  moving  ice  in 
the  depressions  of  the  preglacial  surface,  while  the  rest,  consisting  chiefly  of 
the  coarser  material,  continued  at  the  ice-foot,  and  was  left  as  an  irregular 
ridge  on  the  final  retreat  of  the  glacier.  Very  few  of  these  morainic  belts 
have  as  yet  been  definitely  located,  but  the  following  may  be  mentioned  as 
some  that  have  been  examined  in  late  years  and  whose  character  is  pretty 
certainly  known. 

On  Uie  western  margin  of  the  Winnipeg  basin,  a  rugged  morainic  ridge 


i 


CANADIAN   TKRMINU8  OF   THE   MIHMUUUI   COTEAU. 


300 


runs  along  the  face  of  the  northern  continuation  of  the  Pembina  eHoarpment, 
with  a  mean  elevation  of  1,600  feet.  In  the  great  depression  drained 
by  the  Valley  river  its  width  is  from  a  quarter  to  half  a  mile.  It  is  com- 
posed chiefly  of  sand,  but  it  also  contains  very  many  large  bowlders  of  dark- 
gray  and  reddish  gneiss,  mingled  with  others  of  Paleozoic  limestone. 

Proceeding  a  little  further  to  the  west,  the  whole  surface  of  Duck  mount- 
ain is  found  to  consist  of  irregular  ridges  and  knolls  of  gneissio  debris  ris- 
ing in  some  parts  to  a  height  of  2,000  feet  above  Lake  Winnipeg,  or  2,700 
feet  above  the  sea.  This  rugged  tract  extends  southward  over  the  summit 
of  the  Riding  mountain,  and  it  is  not  improbable  that  the  Brandon  hills 
(which  have  been  described  to  me  as  having  somewhat  similar  characters  to 
those  already  mentioned)  may  be  a  southern  continuation  of  the  same  ex- 
tensive ridge. 

Proceeding  still  farther  westward  alongthe  Forty-ninth  parallel  of  north  lati- 
tude to  the  westward  margin  of  what  has  been  known  as  the  second  prairie 
steppe,  a  wide  belt  of  rounded  morainic  hills  is  reached,  lying  on  a  sloping  pre- 
glacial  surface  rising  gradually  from  east  to  west.  This  hilly  country,  which 
has  been  known  since  the  time  of  the  early  voyageurs  as  the  Missouri  Coteau, 
was  well  described  by  Dr.  Dawson  in  his  report  on  the  geology  and  resources 
of  the  Forty-ninth  parallel.  It  has  also  been  identified  by  Professor  T.  C. 
Chamberlin  as  the  continuation  of  the  great  terminal  moraine  of  the  second 
glacial  period,  which  has  been  traced  by  himself  and  others  from  Dakota 
eastward  to  the  Atlantic  Ocean.  From  the  northern  boundaries  of  Dakota 
it  has  been  traced  by  Mr.  McConuell  northwestward  in  Canada  for  two  hun- 
dred miles  to  a  point  on  the  South -Saskatchewan  river,  twenty-five  mile  above 
the  elbow,  crossing  the  line  of  the  Canadian  Pacific  railway  in  the  vicinity 
of  Secretan  station.  North  of  this  point  its  course  is  not  at  present  known, 
and  it  must  be  borne  in  mind  that  north  of  the  Fifty-first  parallel  of  north 
latitude  the  plains  lose  to  a  great  extent  their  eastern  slope,  the  summits 
of  the  Duck  mountain,  in  long.  101°  W.,  being  equal  in  height  to  the  gen- 
eral surface  of  the  country  due  west  of  them  in  long.  113°  W.,  or  more  than 
five  hundred  miles  distant.  Since,  then,  the  slope  on  which  the  moraine  con- 
stituting the  Missouri  Coteau  was  deposited  becomes  very  indefinite  or  dies 
out  a  little  north  of  the  South-Saskatchewan  river,  it  is  not  improbable  that 
the  course  of  the  moraine  itself  is  much  changed,  so  that  it  may  curve  around 
and  join  others  that  are  now  known  to  the  east  or  west  of  it.  It  is,  however, 
more  probable  that  it  is  here  an  interlobate  moraine,  and  that  as  a  definite 
entity  it  does  not  extend  much  further  north  than  its  present  known  limit. 

West  of  the  Coteau  the  till  is  of  essentially  the  same  character  as  that  to 
the  east  of  it,  and  numerous  detached  ridges  of  "  rolling  hills  "  or  terminal 
moraines'are  known  to  occur.  In  describing  the  vicinity  of  the  Cypress 
hills  Mr.  R.  S.  McConnell  classes  with  the  Coteau,  as  being  "  covered  with 


; 


4()0 


.1.  B.  TYHKKLL— l-OHT-TKRTIARY  DKl'OHITM  OV   MANITOBA. 


■teep-sided  drifl-built  bilb,"  the  "  ridge  extending  northweat  from  Pinto- 
hone  butte  "  (near  the  head  of  the  middle  branch  of  Old  Wives  creek  and 
in  approximate  lat.  49''  45'  N.,  long.  lO?**  45'  W.)  in  a  general  direction 
parallel  to  the  Coteau  and  about  fifty  mileti  south weat  from  it,  and  the  "  npur 
south  of  the  west  end  of  the  Cypress  hilU  "  a  hundred  miles  still  farther 
west. 

West  of  this  ridge  and  south  of  lat.  61"  N.  no  terminal  moraines  have 
Iteen  recognized,  except  such  as  have  been  formed  by  glaciers  flowing  from 
the  valleys  in  the  mountains,  these  being  characterized  by  the  angularity  of 
the  included  pieces  of  rook  and  the  absence  of  eastern  erratics.  North  of 
lat.  51"  N.  there  are  a  number  of  ridges  of  distinctly  morainic  character. 
One  of  the  most  typical  of  these  surrounds  the  southern  and  eastern  sides  of 
the  Hand  hills.  These  latter  hills  form  a  high  table-land  rising  twelve  hun- 
dred feet  above  the  surrounding  plains,  and  are  surmounted  by  two  hundred 
and  seventy  feet  of  sands,  silts,  and  gravel  of  Miocene  age.  Towards  the 
northwest,  west,  and  southwest  they  rise  in  an  abrupt  escarpment  five  hun- 
dred feet  to  their  summit;  towards  the  east  and  southeast  they  decline  grad- 
ually and  regularly  for  a  short  distance,  and  then  the  slope  is  covered  with 
a  ridge  of  rounded  knob-like  hills  separated  by  deep  kettle  holes,  in  the  bot- 
toms of  which  often  nestle  small  isolated  lakes.  Their  summits  are  thickly 
overstrewn  with  bowlders. 

From  fifty  to  sixty  miles  further  north,  near  the  southerly  bend  of  the 
Red  Deer  river,  another  similar  ridge  is  met  with,  the  knolls  rising  in  many 
places  to  more  than  two  hundred  feet  above  the  bottoms  of  the  depressions. 

Turning  directly  eastward  a  rough,  irregular  tract,  known  as  the  Neutral 
hills,  is  seen,  the  higher  points  of  which  are  thickly  covered  with  gneissic 
and  limestone  erratics,  lying  on  a  base  of  unmodified  morainic  material. 
The  hills  themselves  lie  on  an  elevated  plateau  of  Cretaceous  shale,  which 
has  been  very  irregularly  eroded,  so  that  it  is  often  diflicult  to  say  without 
sdctions  whether  an  individual  hill  is  a  product  of  denudation  or  is  one  of 
the  irregularities  of  the  moraine. 

North  of  the  Battle  river  the  Blaokfoot  hills  form  another  area  of  deep, 
unconnected  depressions  and  high,  rounded  knolls,  sprinkled  over  with 
bowlders  of  eastern  gneiss. 

Other  morainic  belts  doubtless  occur  in  this  area  south  of  the  North-Sas- 
katchewan river,  but  as  yet  they  have  not  been  traced  out.  Enough  has 
been  done,  however,  to  show  the  former  existence  of  a  great  glacier,  or  "  mer 
de  glace,"  which  spread  over  the  plains  from  a  source  or  sources  of  supply 
on  or  north  of  the  Archean  rocks  to  the  east,  and  which  flowed  in  a  southerly 
and  southwesterly  direction  almost  to  the  foot  of  the  Bocky  Mountains, 
from  whose  valleys  numerous  small  glaciers  flowed  eastward  to  'join  the 
mighty  advanutng  ice-sheet,  leaving  intervening  areas  along  the.fooit  of  the 
mountains,  and  roughly  west  of  the  3,000-foot  contour  line,  unglapiated. 


OLACIKR   PROnABLY   TRRMINATRD   ID  STANDINO   WATER.        401 

Absence  of  Terminal  Moraines  near  the  Roeky  Mountaifu. — The  nl)8once  of 
a  terminal  moraine  at  the  extreme  western  limit  of  the  till,  near  the  foot  of 
the  mountains,  is  a  fact  worthy  of  notice,  especially  in  view  of  the  fact  that 
the  till  of  both  the  earlier  and  later  glacial  periods  is  found  to  extend 
approximately  the  same  distance  westward,  and  that  there  is  a  narrow  belt 
from  thirty  to  one  hundred  miles  in  width  that  would  appear  never  to  have 
been  covered  by  the  ice-sheet. 

The  most  efficient  reason  that  suggests  itself  to  me  to  account  for  this  state 
of  affairs  is  that  the  glacier  terminated  in  one  or  more  lakes,  hemmed  in 
between  the  continental  glacier  and  the  mountains  and  cut  off  towards  the 
north  and  south  by  lateral  glaciers  flowing  eastward  in  such  valleys  as  those 
of  the  Bow  and  North-Saskatchewan  rivers.  The  morainio  accumulation 
would  in  that  case  be  carried  off  either  by  icebergs  or  waves  and  currents 
and  spread  out  some  distance  beyond  the  limit  of  the  till.  This  would 
account  for  the  presence  of  eastern  erratics  along  the  very  foot  of  the 
mountains,  and  may  also  account  for  the  high  terraces  on  the  sides  of  such 
valleys  as  that  of  the  North  Kootanie  river.  This  condition  could  not, 
however,  have  lasted  for  any  great  length  of  time,  as  no  considerable  amount 
of  stratified  deposits  are  found  in  this  unglaciated  area. 

Western  Pebbles. — The  presence  of  western  pebbles  in  the  drift  far  out  on 
the  plains  was  for  a  long  time  an  almost  insuperable  barrier  to  the  general 
acceptance  of  the  belief  in  its  essentially  eastern  origin ;  but  the  discovery 
of  large  areas  of  Miocene  conglomerates,  holding  these  same  pebbles,  as  far 
east  as  long.  107"  W.,  has  almost  entirely  overcome  this  objection  in  furnish- 
ing new  centres  of  distribution  from  which  these  pebbles  have  been  carried. 
Still  it  is  not  improbable  that  some  of  the  drift  in  the  extreme  western  part 
of  the  drift-covered  country  is  derived  from  the  mountains,  having  been 
carried  down  by  the  local  glaciers  mentioned  above. 

Direction  of  Ice  Flow. — In  speaking  of  the  general  direction  of  flow  of 
the  western  portion  of  the  great  continental  mer  de  glace  it  has  been 
customary  to  regard  it  as  having  advanced  southwestward  from  the  Archean 
area — and  certainly  this  was  the  direction  of  glacial  motion  when  the  ice 
first  reached  the  Winnipeg  basin, — but  recent  investigations  have  shown 
that  in  two  cases,  at  all  events,  this  direction  was  not  sustained,  viz.,  in  the 
great  Winnipeg  valley,  and  in  the  valley  of  the  upper  Assiniboine,  west  of 
the  Duck  and  Biding  mountains.  In  both  these  oases  the  direction  of  flow 
was  southward  or  southeastward  in  the  direction  of  the  trend  of  the  valleys, 
and  parallel  to  the  main  axis  of  the  Rooky  Mountains.  This  direction  was 
in  all  probability  sustained  by  the  glacier  all  the  way  across  the  Canadian 
plains,  and  we  have  thus  one  reason  for  its  great  extent,  as  the  ice  was  moving 
from  a  wide  area  of  distribution  to  a  much  narrower  area  of  dissipation, 
and  there  would  be  a  constant  tendency  to  make  up  for  the  loss  from  the 
surfiuM  by  a  crowding  in  from  the  sides. 


402 


J.  B.  TYRRELL — POST-TERTIARY   DEPOSITS   OF   MANITOBA. 


DeposiU  of  Isolated  Olaeierg. — After  the  final  retreat  of  the  general  con- 
tinental glacier,  relatively  small  n£v6s  remained  on  the  tops  of  some  of  the 
higher  elevations  that  had  previously  been  overridden,  and  small  glaciers 
flowed  outwards  from  them  down  valleys  of  various  depths.  The  Duck 
mountain  shows  many  evidences  of  having  passed  this  intermediate  stage  of 
local  glaciation.  It  is  a  high  table-land,  the  summit  of  which  rises  2,700 
feet  above  the  sea,  or  2,000  feet  above  L  ike  Winnipeg,  and  consists  entirely 
of  Cretaceous  clays  overlain  by  a  great  thickness  of  unstratified  till  and 
transported  bowlders,  most  of  the  latter  being  Archean  gneisses  and  schists. 
From  the  summit  of  the  mountains  several  large  valleys  carry  the  super- 
fluous drainage  outwards  to  the  vrious  surrounding  waterways.  The  strati- 
fled  deposits  in  these  valleys  are  in  many  cases  overlain  by  unstratified  till. 
The  valleys  are  also  blocked  by  small  local  moraines,  behind  which  in  some 
cases  the  valleys  are  terraced  as  high  as  the  tops  of  the  moraines,  while  in 
others  the  rivers  that  formerly  occupied  them  have  been  permanently  di- 
verted into  other  channels. 

Thus  we  would  appear  to  have  in  this  area  three  distinct  bowlder  clays, 
two  formed  by  the  continental  glacier  moving  southward,  and  the  third  or 
upper  formed  by  local  glaciers  existing  at  the  same  time  that  the  great  post- 
glacial lakes  filled  all  the  adjacent  depressions. 

Drumlim. — Over  the  great  portion  of  the  plains  drumlius  have  not  been  rec- 
ognized, possibly  in  part  because  in  the  press  of  other  work  they  have  not  been 
looked  for  sufliciently ;  but  in  the  northern  portion  of  Lake  Winnipegosis 
many  excellent  examples  are  to  be  seen.  They  here  form  groups  of  narrow, 
very  much  elongated  elevations  in  the  till,  rising  in  islands  a  few  feet  above 
the  surface  of  the  lake,  and  are  generally  thickly  covered  with  transported 
bowlders  of  gneiss  and  limestone.  A  very  casual  glance  at  these  groups  of 
islands  will  serve  to  show  that  they  are  structurally  diflerent  from  neighbor- 
ing ones  underlain  by  rock  and  on  which  the  bowlders  have  been  shoved  by 
the  ice.  There  is  no  sign  of  any  rock  in  place  and  the  stones  are  not  all  of 
constant  lithological  character,  as  is  generally  the  case  where  the  rock  is 
close  to  the  surface,  but  they  are  true  transported  bowlders,  difiering  as  widely 
from  each  other  as  crystalline  gneiss  and  coralline  limestone.  The  islands 
are  also  formed  with  their  long  axes  parallel  to  the  direction  of  the  glacial  strise 
in  the  vicinity. 

The  Aqueous  Deposits. 

Interglaeial  Deposits. — As  has  been  already  shown,  the  evidences  of  a  re- 
currence of  glacial  conditions  and  the  intervening  temperate  era  near  the 
northwestern  limit  of  the  glaciated  area  leave  no  room  for  doubt  that  the 
glacier  retired  for  a  considerable  time  from  the  greater  part  of  the  western 
prairie  region ;  and  perhaps  during  this  interglaeial  period  conditions  may 


., 


ECONOMICALLY   IMPORTANT    AQUEOUS   DEPOSITS. 


4on 


have  been  much  as  they  are  now,  for  near  the  northern  end  of  the  Duck 
mountains  there  is  a  deposit  of  stratified  silt  underlying  a  great  thickness 
of  unstratified  till,  and  probably  of  inter-glacial  age,  holding  numerous 
fresh-water  shells,  with  fragn?ent8  of  plants  and  fish  remains  essentially  the 
same  as  those  living  in  Lake  Manitoba  and  the  surrounding  lakes  to-day. 

Karnes. — Very  few  kames  have  up  to  the  present  been  definitely  located 
in  the  Canadian  northwest,  and  none  that  would  ap]iear  to  have  been  con- 
nected  with  any  but  the  later  stage  of  glaciation,  viz.,  that  of  isolated  local 
glacial  centres.  The  most  important  of  these  stretch  as  straight  ridges  down 
the  middles  of  deep  valleys  on  the  east  side  of  the  Duck  mountain.  The 
two  most  important  ones  recognized  were  covered  by  several  feet  of  pebbly 
unstratified  till,  the  same  as  that  composing  the  surrounding  hills.  In  some 
cases  what  have  been  taken  for  moraines  may  possibly  be  kames,  but  it  is 
diflicult  in  all  cases  to  distinguish  them  in  the  absence  of  sections. 

Laetutral  Beda. — Resting  on  the  bowlder  clay  throughout  very  extensive 
tracts  in  Manitoba  and  the  North  West  territories  are  stratified  sands,  silts> 
and  clays  that  have  been  deposited  in  the  bottoms  of  post-glacial  or  recent 
lakes.  The  delineation  of  these  lake  basins  is  a  work  of  the  greatest  economic 
importance,  as  it  is  evident  from  what  we  at  present  know — that  many  of  the 
most  fertile  tracts  in  the  west  are  underlain  by  rich  alluvial  clays  deposited 
in  the  bottoms  of  sheets  of  water  of  greater  or  less  extent,  which  have  now 
disappeared. 

The  number  and  extent  of  most  of  these  old  lakes  has  not  as  yet  been  de- 
termined, but  the  positions  of  a  few  may  be  here  generally  indicated. 

The  country  drained  by  the  upper  waters  of  the  Bow,  Red  Deer,  and  North- 
Saskatchewan  rivers,  having  at  present  a  mean  elevation  of  between  two 
and  three  thousand  feet,  was  largely  submerged,  fine  clays  and  silts  over- 
lying the  till  being  here  very  generally  met  with,  though  no  shore  lines  have 
been  recognized.  A  marked  peculiarity  of  these  deposits  is  the  utter  absence 
in  them  of  any  shells  or  other  fossils  that  would  indicate  the  existence  of 
life  in  the  lakes  in  which  they  were  deposited. 

Another  extensive  stratified  deposit  skirts  the  eastern  margin  of  the  Mis- 
souri Coteau. 

The  depression  lying  west  of  the  Duck  mountain,  which  is  now  drained 
southward  by  the  Assiniboine  river,  was  also,  at  the  close  of  the  glacial 
period,  the  basin  of  a  large  lake  which  first  drained  eastward  through  the 
valley  of  Short  creek  and  Valley  river,  between  the  Duck  and  Riding 
mountains,  and  afterwards,  when  this  valley  was  blocked  by  a  local  glacier 
from  the  Duck  mountain  (the  terminal  moraine  of  which  still  stretches 
across  its  western  end),  cut  out  the  present  valley  of  the  Assiniboine.  South- 
ward, this  lake  extended  down  to  lat.  51°  N.  Its  northern  and  western 
boundaries  have  not  yet  been  determined ;  but  standing  on  the  morainic 

LIII— Bum..  Okoi..  Soc.  Am.,  Vot..  1, 1889. 


i 


404        J.  B.  TYRRELL — P08T-TKRT1ARY  DEPOSITS  OF   MANITOBA. 

ridge  that  forms  the  western  side  of  the  Duck  mountain,  and  which  was  also 
the  eastern  shore  of  the  lake,  a  wide,  level,  alluvial  plain  or  lake  bottom  may 
be  seen  stretching  westward  to  the  limits  of  vision. 

But  by  far  the  largest  and  most  important  of  these  ancient  post-glacial 
lakes  is  that  named  Lake  Agassiz  by  Mr.  Warren  Uphara,  and  which  once 
occupied  the  Winnipeg  basin  and  the  valley  of  Red  river.  In  its  bed  was 
deposited  the  rich  alluvial  clay  that  is  now  enabling  Manitoba  to  take  its 
place  as  one  of  the  foremost  wheat-producing  areas  in  the  world. 

Ancient  Beaches. — I  shall  not  now  discuss  the  altitude,  length,  and  depth 
of  these  lakes;  but  a  few  words  may  be  said  of  the  beaches  that  at  various 
times  formed  the  shore  lines  for  the  gradually  receding  waters. 

The  existence  of  the  old  shores  of  Lake  Agassiz  was  clearly  pointed  out  by 
Professor  H.  Y.  Hind  in  1859,  but  their  relative  heights  were  not  at  all 
understood  by  him.  Of  late  years  Mr.  Warren  Upham  has  carefully  studied 
these  beaches  from  Lake  Traverse,  at  the  south  end  of  the  Red  river  valley, 
to  a  short  distance  north  of  the  50th  parallel  of  north  latitude.  In  the 
wooded  district  further  north,  and  one  hundred  and  fifly  miles  north-north- 
west from  where  the  old  lake  beaches  cross  the  international  boundary  at 
the  foot  of  the  Pembina  escarpment,  several  gravel  ridges  were  located  by 
the  writer  on  the  northern  face  of  the  Riding  mountain,  close  to  the  banks 
of  Ochre  river,  a  small  stream  flowing  into  Lake  Dauphiu.  The  heights  of 
these  ridges  are  respectively  1,215,  1,115,  and  1,025  feet  above  sea  level. 
From  Ochre  river  they  were  followed  for  eighteen  miles  in  a  northwesterly 
direction,  a^  the  end  of  which  distance  the  highest  one  runs  along  the  summit 
of  a  steep  escarpment  one  hundred  feet  in  height,  while  the  one  below  it  is 
continuous  with  the  line  of  the  base  of  the  cliff.  The  face  of  the  cliff  is  now 
overgrown  with  trees,  but  a  gulley  that  cuts  back  into  it  shows  it  to  be  com- 
posed of  the  white  limestones  and  ohalk-marls  of  the  Niobrara  subdivision 
of  the  Cretaceous. 

The  sequence  of  events  is  here  very  beautifully  shown :  For  a  cr  nsidera- 
ble  time  the  lake  stood  at  the  level  of  the  highest  of  these  beaches,  au.-^  the 
land  sloped  gradually  beneath  the  surface  of  the  water.  The  lake  then  fell 
more  or  less  rapidly  a  hundred  feet  to  the  next  lower  shore  line,  and  must 
have  stood  at  this  level  for  a  long  time,  sufficiently  long  at  all  events  to 
allow  the  waves  to  cut  a  cliff  of  limestone  one  hundred  feet  in  height  from 
what  was  before  a  gradually  declining  surface. 

From  this  chalk  cliff,  which  formerly  must  have  stood  out  boldly  as  a 
conspicuous  landmark  on  the  shore  of  Lake  Agassiz,  coast  ridges  were  again 
followed  and  crossed  at  intervals  in  travelling  northward  to  Valley  river. 
This  stream  flows  in  a  wide  depression  separating  Duck  from  Riding  mount- 
ains.  The  highest  beach  ridge  seen  on  its  banks  has  an  elevation  of  1,280 
feet  above  the  sea,  but  above  this  is  an  extensive  sandy  plain  covered  with 


'X 


BEACHES   OF   LAKE   AOASSI^S. 


405 


t< 


stunted  grass  and  dotted  with  a  few  scrubby  oak  trees.  This  plain  is  a 
delta  deposit  of  a  river  that  flowed  into  Lake  Agassiz  when  this  lake  was  at 
its  highest  stage ;  and  on  the  sides  of  the  channel  which  the  present  river 
has  since  cut  through  the  plains  a  number  of  very  interesting  and  instruct- 
ive sections  can  be  seen,  including  both  the  superficial  deposits  and  the  un- 
derlying Cretaceous. 

Beyond  the  Valley  river  the  ridges  continue  in-  a  direction  15°  west  of 
north  for  sixty  miles,  to  the  northeast  angle  of  the  Duck  mountain,  when 
they  turn  abruptly  westward  into  the  valley  of  Swan  river.  Crossing  ,this 
valley  they  are  well  marked  on  the  eastern  face  of  the  Porcupine  mountains, 
north  of  which  they  turn  westward  for  a  long  distance  into  the  vallay  of 
Red  Deer  river,  ending  in  a  wide,  flat,  sandy  delta  plain. 

Whether  they  extend  along  the  face  of  the  Pasquia  mountain  has  not 
yet  been  determined ;  but  the  Pas  ridge  on  the  Saskatchewan  river  would 
appear,  from  descriptions  we  have  of  it,  to  be  one  of  these  ancient  beach 
ridges,  though  its  elevation  is  not  nearly  so  great  as  most  of  the  well  defined 
ridges  along  the  face  of  the  Duck  and  Porcupine  mountains. 

These  beaches  as  a  rule  are  in  the  form  of  slightly  rounded  ridges  from 
flfly  to  two  hundred  feet  1^^  raised  from  three  to  twenty-five  feet  above 
the  surrounding  country.  They  are  composed  of  sand  and  small  water- 
worn  pebbles,  a  few  of  which  are  granitic  or  quartzitic,  while  a  great  ma- 
jority are  of  the  white  Paleozoic  limestone  at  present  outcropping  around 
the  adjoining  lakes.  The  gravel  must,  however,  have  been  derived  entirely 
from  the  till  that  had  previously  been  carried  by  the  glacier  from  the  bedded 
rock  at  a  distance,  for  there  is  now  no  known  outcrop  of  these  limestones 
with  a  greater  elevation  than  about  nine  hundred  and  thirty  feet,  or  more 
than  five  hundred  feet  below  the  summit  of  the  highest  of  the  gravel  ridges. 
Cliffii  of  till  that  might  furnish  sources  of  supply  for  the  pebbles  are  also 
often  separated  by  very  long  intervals ;  so  that  it  is  probable  that  most  of 
the  gravel  was  brought  down  by  rapid  streams  flowing  from  the  adjoining 
mountains,  and  was  distributed  by  currents  along  the  shore. 

The  beaches  would  appear  essentially  to  have  been  formed  by  waves  and 
currents,  as  there  are  very  few  signs  of  ice  action  such  as  are  seen  around 
the  shores  of  Lakes  Winnipegosis  and  Manitoba  to-day. 

Where  most  conspicuously  developed  the  beaches  are  covered,  as  a  rule, 
with  only  a  meagre  growth  of  short  grass,  which  in  some  of  the  more  north- 
ern parts  is  varied  with  a  few  stunted  trees  of  Banksian  pine.  They  thus 
often  form  beautiful  dry  roads  through  country  that  would  otherwise  be  an 
impenetrable  forest. 

So  far  as  the  eye  can  detect,  the  line  of  the  crest  of  the  ridge  is  quite 
horizontal,  but  careful  measurements  show  it  to  rise  gradually  and  regularly 
towards  the  north,  just  as  the  crests  do  in  Minnesota  and  Dakota.    At 


406        J.  B.  TYRKELL — POST-TERTIARY  DEPOSITS   OF   MANITOBA. 

the  boundary  line  the  ridges  range  in  altitude  from  995  to  1,230  feet  above 
the  sea,*  while  on  the  eastern  face  of  the  Duck  and  Riding  mountains  they 
were  found  to  ascend  as  high  as  1,460  feet  above  the  sea,  showing  a  rise  in 
the  upper  boundary  beach,  supposing  it  to  continue  this  far  north,  of  about  one 
foot  to  the  mile  from  the  point  of  crossing  latitude  40°  north  to  the  Duck 
river,  where  the  highest  beach  was  seen.  If  the  highest  beuch  at  the  bound- 
ary does  not  extend  so  far  north,  the  rise  per  mile  will  be  somewhat  greater. 

Very  few  fossils  that  can  be  clearly  identified  have  been  found  in  these 
gravel  ridges;  but  on  Valley  river  in  lat.  51°  13'  N.,  long.  100°  20'  W.,  at 
a  distance  of  two  feet  below  the  surface,  some  roughly  cliipped  fragments  of 
quartzite  have  been  discovered,  lying  horizontally  among  the  di8k-shai)ed 
waterworn  pebbles,  along  with  a  small  bone  of  a  mammal.  Precisely  simi- 
lar fragments  are  now  to  be  found  on  the  shores  of  lakes  Winnipegosis  and 
Manitoba  in  association  with  well-formed  arrow-points,  and  the  traditions 
of  the  Indians  go  back  to  the  time  when  they  were  formed  and  used  by  their 
forefathers.  As  the  gravel  had  been  laid  down  by  water  action  and  was 
quite  undisturbed,  they  clearly  indicate  the  existence  of  man  at  the  time 
when  this  lake  beach  was  being  thrown  up,  and  it  is  probable  that  here, 
near  the  mouth  of  the  former  representative  of  Valley  river,  was  one  of  his 
favorite  haunts.  The  summit  of  the  beach  in  which  these  "  chipped  flints  " 
were  found  is  425  feet  above  lake  Winnipeg  or  1,135  feet  above  the  sea. 

The  positions  of  the  northern  and  eastern  shores  of  Lake  Agassiz  have  not 
yet  been  determined  ;  but  from  what  we  know  at  present  we  can  safely  say 
that  there  is  no  laud  in  that  direction  sufficiently  high  to  form  a  shore  luie 
with  an  elevation  of  1,400  or  more  feet,  and  there  has  been  no  evidence  forth- 
coming to  show  that  there  has  been  any  other  disturbance  of  the  country 
since  the  lake  was  at.  its  highest  level  than  the  slow  uplift  towards  the 
north  shown  by  the  gradual  rise  of  the  ridges  in  that  direction.  The  theory 
has  been  suggested  that  the  face  of  the  retreating  continental  glacier  held 
back  the  water  on  these  two  sides.  It  is  not  improbable  that  as  the  glacier 
retired  from  the  face  of  the  country,  which  was  sloping  towards  it,  a  lake 
would  be  formed  at  its  foot.  If  this  be  the  true  explanation  of  the  cause  of 
the  formation  of  Lake  Agassiz,  it  discharged  its  surplus  water  through  the 
valley  of  Lake  Traverse  until  the  glacier  had  retired  far  enough  or  had 
decreased  sufficiently  in  size  to  allow  of  a  discharge  for  the  lake  over  or 
around  it.  The  position  of  this  river  has  not  been  and  may  possibly  never 
be  determined,  as  all  traces  of  it  may  have  since  been  swept  away. 

Much  has  yet  to  be  learned  of  the  history  of  all  of  these  post-glacial  lake 
beaches,  but  a  long  array  of  interesting  facts  is  now  being  gathered  together, 
which  it  is  hoped  will  before  long  solve  some  of  the  mysteries  of  Quater- 
nary dynamical  geology. 

*The  Upper  BeMhes  and  Deltas  of  the  Glacial  Lake  AgasBli,  by  Warren  Upham:  Bull.  80  U.  S. 
Geol.  Survey,  1887,  p.  IT. 


DISCUSSION. 


Mr.  J.  £.  MiLi^ :  I  should  like  to  mention,  in  connection  with  this  paper, 
General  Warren's  account  of  the  cafion  of  the  Mississippi.  He  traced  the 
Mississippi  cafion  up  to  that  of  the  Ked  river,  and  thence  on  to  Lake  Winni- 
peg. He  inferred  from  what  he  saw  that  the  cafion  when  first  formed  was 
higher  than  now,  and  that  the  waters  of  the  Winnipeg  flowed  at  that  eleva- 
tion southward.  He  inferred,  also,  that  the  cafion  was  formed  by  a  river 
much  larger  than  the  present  Mississippi.  General  Warren  announced  this 
about  1869.  I  had  the  pleasure  of  doing  a  part  of  the  geological  work  of 
his  survey.  If  I  understand  Professor  Cbamberlin  rightly,  the  cafion  was 
excavated  between  the  two  glaciations.  In  that  intermediate  period  the 
drainage  of  Lake  Winnipeg  was  southward  through  the  Mississippi  valley, 
and  if  General  Warren's  account  is  correct,  the  country  north  of  Lake 
Winnipeg  must  have  been  drained  southward.  Professor  Chamberlin  shows 
that  at  this  very  time  the  country  of  the  lower  Mississippi  was  at  base  level — 
was  very  low.  There  certainly  was  an  elevation,  therefore,  that  caused  the 
erosion  of  the  Mississippi  cafion  about  that  time.  This  seems  to  confirm  and 
strengthen  General  Warren's  deduction  that  there  was  an  elevation,  and 
an  elevation  increasing  northward.  I  should  like  to  have  Mr.  Tyrrell  state 
what  bearing  his  observations  have  upon  this  deduction  of  General  Warren's. 

Mr.  Tyrrell  :  The  problem  of  the  direction  of  the  preglacial  drainage  of 
the  Lake  Winnipeg  basin  is  a  long  and  complex  one.  I  can  merely  say  here 
that  much  of  the  evidence  at  present  in  hand  goes  to  show  that  it  was  drained  by 
a  river  flowing  with  a  more  or  less  northerly  course.  I  know  of  no  evidence 
found  in  Canadian  territory  that  will  serve  to  indicate  the  direction  of  drain- 
age in  the  interval  between  the  first  and  second  glacial  periods.  In  the 
Winnipeg  basin  the  tracks  of  the  older  glacier  have  been  obliterated  or 
greatly  obscured  by  the  severe  erosion  of  the  later  glacier.  Generally  speak- 
ing, one  must  look  farther  south  or  nearer  the  ancient  ioe-front  for  the  clearest 
evidence  of  the  earlier  glaciation,  though  it  is  quite  probable  that  iuter- 
glacial  beds  exist  in  Manitoba.  In  the  postglacial  period  the  Winnipeg 
basin  was  first  drained  southward  through  the  valley  of  Lake  Traverse  and 
down  the  Minnesota  river,  and  afterwards  in  a'  northerly  or  northeasterly 
direction,  as  at  present. 

On  this  latter  subject,  however,  I  beg  to  refer  to  President  Chamberlin, 
who  has  given  the  matter  a  large  amount  of  attention. 

President  T.  C.  Chamberlin  :  The  cutting  of  the  trench  from  the  outlet 
of  Lake  Agassiz  down  to  the  Mississippi  was  a  work  which  followed  the 
main  glaciation  of  the  second  period,  and  was  not  a  part  of  the  great  trench- 
ing of  the  Mississippi  to  which  I  referred  in  my  paper. 

(407) 


408        J.  li.  T YKKELL — I'OST-TKKTIAKY  DEPOSITS   OF   MANITOBA. 


I  think  we  should  be  scarcely  less  than  stolid — we  of  the  United  States — 
if  we  did  not  strike  hands  with  our  brethren  across  the  border  over  a 
paper  which  brings  into  such  beautiful  consonance  the  phenomena  on  the 
two  sides  of  the  international  boundary.  This  paper  sets  forth  the  phe- 
nomena of  the  great  plains  on  the  north  of  the  boundary  in  precisely  the 
same  terms  and  under  the  same  interpretations  that  we  have  been  accustomed 
to  use  on  our  side  of  the  line. 

That  which  strikes  me  most,  beyond  this  gratifying  consonance,  is  the 
remarkable  extension  of  our  knowledge  which  this  paper  and  the  two  pre- 
ceding  papers  relating  to  the  northwestern  part  of  our  continent*  give  us 
with  respect  to  the  delimitation  of  the  ice  sheets.  The  boundary  line  in  the 
western  portion  of  the  plains  of  the  Dominion  has  been  represented  as  ex* 
tending  nearly  parallel  with  the  foot  of  the  Rocky  Mountains  down  to.  our 
boundary.  It  continues  essentially  parallel  to  the  Rocky  Mountains  south- 
ward in  our  territory  to  the  vicinity  of  the  Sun  river,  then  curves  east  and, 
crossing  the  Missouri  river,  swings  northward  on  the  north  flank  of  the 
Lightwood  mountains,  and  thence  northeast  until  it  strikes  the  Missouri 
again  at  the  mouth  of  the  Judith  river ;  then,  swinging  back,  it  courses  east 
to  the  vicinity  of  Bismarck,  where  it  once  more  turns  south  and  keeps  near 
the  course  of  the  Missouri  river  until  it  strikes  the  Mississippi.  So  the  de- 
limitation in  the  western  portion  of  the  Dominion  is  brought  into  perfect 
harmony  with  that  reported  by  the  United  States  Geological  Survey. 
Taking  this  in  connection  with  the  facts  given  in  the  preceding  paper,  it  is 
scarcely  a  jump  of  interpretation  to  project  this  line  along  the  foothills  of 
the  Rocky  Mountains  north  to  the  border  observed  in  the  Mackenzie  basin, 
and  thence  on  to  the  delta  of  the  Mackenzie,  which  practically  carries  the 
delimitation  to  the  Arctic  sea. 

The  limitation  of  this  border  to  a  line  off  the  eastern  base  of  the  Rocky 
Mountains  is  a  remarkable  fact  when  we  consider  the  low  condition  of  the 
plains  east  of  them ;  and  the  further  fact  that  the  glaciers  of  the  Rocky 
Mountains  had  only  a  moderate  extension  is  very  remarkable.  We  must  bear 
in  mind  that  these  mountains  are  very  high  and  very  broad,  and  that  there 
sweep  over  them  breezes  bearing  an  unusual  load  of  moisture,  much  more 
than  the  winds  that  sweep  over  the  Scandinavian  mountains  on  the  other 
side  of  the  Atlantic.  Yet,  nothwithstanding  all  these  highly  favorable  con- 
ditions, they  were  not  the  source  of  any  extensive  glaciation,  but,  on  the 
contrary,  the  great  glaciation  came  from  the  far  lower  heights  of  the  eastern 
part 'of  the  continent  and  spread  across  the  vaat  stretches  of  the  great  plains. 
This,  it  seems  to  me,  is  a  fact  of  profound  consequence,  and  its  colossal 
character  ought  not  to  be  overlooked. 

*  By  I.  C.  Russell  and  R.  O.  MoOonnell ;  the  former  prioted  Moong  the  memoirs  (pp.  90-168),  and 
the  latter  in  the  prooeediogs,  Id  this  volume. 


PLEISTOCENE  SUBMEROENOE  ON  THE   ATLANTIC  COAST. 


409 


Professor  N.  S.  SiiAiiER:  I  should  like  to  ask  whether  this  evidence, 
brought  to  us  from  north  of  the  boundary  to  the  United  States,  dues  not  go 
still  further  and  show  that  the  last  glacial  period  in  North  America  was  in 
some  way  connected  with  the  conditions  of  the  northern  Atlantic  ocean  ? 
The  evidence  now  goes  to  show  that  it  is  a  symptom  of  climatic  conditions 
on  the  north  Atlantic ;  and  therefore  it  is  our  task  to  interpret  the  phe- 
nomena by  the  facts  that  have  taken  place  in  that  ocean  basin.  It  seems  to 
me  it  is  by  the  increased  precipitation  of  the  vapors  taken  from  the  warm 
waters  to  the  sea  that  we  may  most  easily  explain  the  conditions  of  the  last 
ice  period. 

I  have  recently  had  an  opportunity  to  study  the  surface  geology  of  Florida, 
and  it  seems  to  me  probable  that  in  the  glacial  times,  or  about  the  time  of 
the  last  glacial  period,  the  Gulf  Stream  flowed  freely  over  the  surface  of 
Florida  up  to  the  northern  portion  of  the  lake  district.  The  appearance 
of  Florida  seems  to  indicate  that  the  tide  at  this  time  extended  from  the 
northern  part  of  the  lake  district  to  the  Cuban  shore.  It  seems  to  me  likely 
that  we  may  attribute  a  glaciation  in  the  eastern  part  of  Europe  and  Asia 
and  the  northern  part  of  North  America  to  the  changes  in  the  flow  of  this 
stream  dependent  on  modifications  of  the  coast  line  topography  of  the  region 
of  the  Caribbean  and  the  Gulf  of  Mexico. 

Mr.  W  J  McGee  :  I  have  recently  ascertained  that  during  early  Pleisto- 
cene time — during  the  first  of  the  two  great  ice  invasions  which  all  geologists 
are  recognizing — not  only  was  all  of  Florida  submerged,  but  two-thirds  of 
Georgia  and  the  greater  part  of  South  Carolina.  The  submergence  in  South 
Carolina  reached  550  or  600  feet,  and  over  the  low-lying  plains  there  lies  a 
mantle  of  coast  sands  deposited  during  the  period  of  submergence.  These 
coast  sands  have  been  found  continuous  with  the  Columbia  formation  of 
the  northern  part  of  the  Atlantic  slope. 

Dr.  J.  W.  Spencer  :  With  the  conclusions  of  Professor  Shaler  and  Mr. 
McGee  I  concur.  I  have  seen  apparent  Pleistocene  deposits  in  Alabama  at 
about  675  feet  above  the  sea.  Over  plains  and  hills  of  the  great  Northwest 
of  Canada,  also,  I  have  seen  bowlders  scattered  upon  the  surface  of  both 
Paleozoic  and  Cretaceous  rocks.  In  many  cases  these  are  of  secondary  origin, 
having  been  left  upon  the  washing  away  of  the  finer  materials  from  the  older 
bowlder  clay.  Few  or  none  of  those  erratics  which  I  have  seen  have  been 
primarily  derived  from  their  original  sources,  although  many  have  been 
again  transported  by  the  floating  ice  of  now  shrunken  or  extinct  lakes  or 
seas. 

From  the  occurrence  of  elevated  beaches  described  by  Mr.  Tyrrell  and 
others  in  the  North  West  territories,  and  from  the  remains  of  still  higher 
beaches  about  the  Great  Lakes,  I  am  inclined  to  generalize  and  bring  down 
the  whole  continent  to  make  the  beaches  mark  sea-level  in  the  last  stages  of 
the  Pleistocene  period  after  the  episode  of  the  last  till. 


410 


J.  n.  TYRRRT-r, — rOST-TERTIARY  DKP08ITS  OF   MANITORA. 


Mr.  Tykrbll  :  I  may  say  a  word  with  regard  to  the  bowhlers  referred  to 
by  Professor  S|)encer  as  scattered  over  the  surface  iii  the  Northwest.  It  is 
being  recognized  by  a  number  of  explorers  that  there  is  probably  some  little 
difference  in  origin  between  the  bowlders  lying  on  the  surface  and  those  in  the 
underlying  bowlder  clay.  In  many  cases  it  is  impossible  that  the  bowlders 
could  have  been  derived  by  denudation  from  the  bowlder  clay  beneath  ;  and 
I  am  rather  inclined  to  suggest  the  explanation  that  those  bowlders  were 
transported  in  the  mass  of  the  glacier  itself  instead  of  having  been  beneath 
it,  as  was  the  till,  and  that  as  the  glacier  melted  and  retired  they  were  dropped 
'  on  the  surface.  I  think  that  this  explanation  will  fairly  account  for  the 
presence  of  most  of  the  solitary  local  bowlders  on  the  surface  of  the  plains, 
where  they  cannot  be  accounted  for  by  erosion. 


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